Research conducted by one of us has confirmed that temperature sensors located in the forehead have an effect on heart rate. Cooler temperatures tend to slow the heart rate, whilst higher temperatures tend to increase the heart rate. It has been demonstrated that there is a connection between increased heart rate and feelings of exertion in office environments. Higher temperatures produce feelings of fatigue despite the amount of real effort being expended. Conversely, lower temperatures, particularly at the hands and feet, tend to create discomfort. Thus, an idealized ambience for a working environment is one which keeps the forehead cool (by maintaining a low ambient temperature) while at the same time providing warmth to the more sensitive areas of the body (hands and feet) to allow physical activity to proceed in comfort. Using this method, it has been demonstrated that performance capability can be maintained.
It is also considered important to provide maximum flexibility in providing localized heat, i.e. by directing the heat to specific targets. All of these concepts have been taken into account in the development of the present device.